The present invention is directed to a walking assistance device incorporating a container system for pressurized fluids that is lightweight and flexible.
There are many applications for a portable supply of fluid under pressure. For example, SCUBA divers and firefighters use portable, pressurized air supplies. Commercial aircraft employ emergency oxygen delivery systems that are used during sudden and unexpected cabin depressurization. Military aircraft typically require supplemental oxygen supply systems as well. Such systems are supplied by portable pressurized canisters. In the medical field, gas delivery systems are provided to administer medicinal gas, such as oxygen, to a patient undergoing respiratory therapy. Supplemental oxygen delivery systems are used by patients that benefit from receiving and breathing oxygen from an oxygen supply source to supplement atmospheric oxygen breathed by the patient. Not uncommonly, patients in need of respiratory therapy also require the assistance of a walking assistance device such as a walking cane, a walking crutch, or a walker. For such requirements, a compact, portable supplemental oxygen delivery system is useful in a wide variety of contexts, including hospital, home care, and ambulatory settings.
High-pressure supplemental oxygen delivery systems typically include a cylinder or tank containing oxygen gas at a pressure of up to 3,000 psi. A pressure regulator is used in a high-pressure oxygen delivery system to step down the pressure of oxygen gas to a lower pressure (e.g., 20 to 50 psi) suitable for use in an oxygen delivery apparatus used by a person breathing the supplemental oxygen.
In supplemental oxygen delivery systems, and in other applications employing portable supplies of pressurized gas, containers used for the storage and use of compressed fluids, and particularly gases, generally take the form of cylindrical metal bottles that may be wound with reinforcing materials to withstand high fluid pressures. Such storage containers are expensive to manufacture, inherently heavy, bulky, inflexible, and prone to violent and explosive fragmentation upon rupture. Mounting such containers to a walking assistance device so as to provide the patient with an ambulatory supply of oxygen can add significant undesired weight and bulk to the device.
Container systems made from lightweight synthetic materials have been proposed. Scholley, in U.S. Pat. Nos. 4,932,403; 5,036,845; and 5,127,399, describes a flexible and portable container for compressed gases which comprises a series of elongated, substantially cylindrical chambers arranged in a parallel configuration and interconnected by narrow, bent conduits and attached to the back of a vest that can be worn by a person. The container includes a liner, which may be formed of a synthetic material such as nylon, polyethylene, polypropylene, polyurethane, tetrafluoroethylene, or polyester. The liner is covered with a high-strength reinforcing fiber, such as a high-strength braid or winding of a reinforcing material such as Kevlar(copyright) aramid fiber, and a protective coating of a material, such as polyurethane, covers the reinforcing fiber.
The design described in the Scholley patents suffers a number of shortcomings which makes it impractical for use as a container for fluids stored at the pressure levels typically seen in portable fluid delivery systems such as SCUBA gear, firefighter""s oxygen systems, emergency oxygen systems, and medicinal oxygen systems. The elongated, generally cylindrical shape of the separate storage chambers does not provide an effective structure for containing highly-pressurized fluids. Moreover, such large containers cannot be easily incorporated onto a walking assistance device. Also, the relatively large volume of the storage sections creates an unsafe system subject to possible violent rupture due to the kinetic energy of the relatively large volume of pressurized fluid stored in each chamber.
Accordingly, there is a need for improved container systems made of light weight polymeric material and which are robust and less susceptible to violent rupture and can be easily incorporated within a walking assistance device, such as a walking cane, a walking crutch, or a walker without adding significant weight or bulk.
In accordance with aspects of the present invention, a walking assistance device includes a gas storage vessel that is robust, unobtrusive, and lightweight. In particular, a walking assistance device providing a portable supply of medicinal gas is disclosed that includes a handle adapted to be grasped by a user, a support structure constructed and arranged to support the handle in a raised position with respect to the ground, and a gas storage vessel carried within the support structure. The gas storage vessel is made up of a plurality of hollow chambers, each chamber having a substantially spherical or ellipsoidal shape and being formed from a polymeric material, a plurality of conduit sections formed from a polymeric material, each conduit section being positioned between adjacent hollow chambers to interconnect the plurality of hollow chambers, each of the conduit sections having a maximum interior transverse dimension that is smaller than a maximum interior transverse dimension of each of the hollow chambers, and a reinforcing filament wrapped around the hollow chambers and the conduit sections.
Other objects, features, and characteristics of the present invention will become apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of the specification, and wherein like reference numerals designate corresponding parts in the various figures.